For centuries, ambitious mariners pining to traverse the Arctic Circle experienced little more than disappointment — and often death.

But diminishing sea ice and more temperate weather have made traveling through polar waters a vacation rather than an exploration.

The area covered by Arctic sea ice in December was 420,900 square miles smaller than the 1981-2010 average, according to the National Snow and Ice Data Center. That represents an area more than one and a half times the size of Texas — and was the second-lowest level recorded by satellite since 1979.

But experts warn that the increasing traffic raises the chance of a catastrophe such as an oil spill or a sewage leak that would damage the pristine polar environment.

“It is a matter of time, not a matter of if,” said Jackie Dawson, an associate professor of geography, environment and geomatics at the University of Ottawa. "We will see some sort of disaster related to climate change and increased human activity in the Arctic."

The Arctic is prone to severe and changing weather conditions that complicate travel and endanger seafarers. The high latitude also disrupts maritime navigational and communication systems. Should an oil spill, a crash or a machinery malfunction occur, the region's remoteness makes an efficient emergency response nearly impossible.

The Northwest Passage — a route through Canada's Arctic Archipelago that is 500 miles north of the Arctic Circle and connects the Atlantic Ocean with the Pacific — was first crossed by sea in 1906.

Personnel stand aboard the Finnish icebreaker MSV Nordica as it arrives in Nuuk, Greenland, last summer. Its 6,214-mile journey marked the earliest transit of the Northwest Passage in history. It left Vancouver on July 5 and reached Nuuk on July 29.David Goldman / AP file

The vast majority of Arctic voyages since then have involved minimalist research vessels, according to Marta Bystrowska, a climate scientist completing her Ph.D. thesis in Arctic tourism at the Centre for Polar Studies at the University of Silesia in Poland.

But guests are increasingly hopping aboard Arctic Circle-bound ships expecting a first-class experience along with "elegant menus, comfortable rooms and additional activities such as diving or kayaking during a cruise,” Bystrowska said. “The cruising industry may shift toward bigger and bigger ships to accommodate rising demand and making cruises more profitable.”

Since Serenity’s maiden voyage, other boutique firms have followed suit. Abercrombie and Kent, a British luxury travel company, offers a 24-day, all-inclusive trip through the Northwest Passage for $30,995. Personalized butler service costs another $10,000.

The Crystal Serenity anchored just outside Nome, Alaska, in 2016. The New York-bound ship made the port call as it became the largest cruise ship to ever go through the Northwest Passage.Mark Thiessen / AP file

Quark Expeditions pushes deeper into the heart of the Arctic with an excursion with prices beginning at $28,695. Passengers can shell out another $500 to view the North Pole from a hot-air balloon.

These ships must withstand the grueling conditions that once made the Arctic the planet's most daunting maritime challenge. The International Maritime Organization introduced a Polar Code in 2016 aimed at ensuring that tour operators were prepared for the remoteness and extreme weather of the Arctic. It also prohibits vessels from discarding food waste and sewage.

While the code is mandatory under two international conventions, its enforcement is up to the IMO's 172 member states. It also does not specify what penalties should be imposed for noncompliance.

“The Arctic is full of magic. It is one of the most beautiful places on earth”

Its lifeboats are fully enclosed, resembling submarines rather than the typical emergency raft. Head-to-toe thermal suits accompany life jackets. Steaming water cascades down its front instead of a traditional defroster. Axes and shovels are on reserve to combat inevitable ice buildups.

And while thinning sea ice has opened up Arctic waters to tourists, it also hints that there is a time limit on such travel.

The National Oceanic and Atmospheric Administration has already warned the region is heating at twice the rate as the rest of globe. As a result, Arctic tourism has taken on a morbid moniker of “last-chance tourism,” which describes the desire for tourists to witness the landscapes and species before they are gone for good.

“Last-chance tourism plays an important psychological role in influencing people’s decision to take cruises sooner rather than later,” said Dawson, of the University of Ottawa. “I often hear people saying that they had been thinking about taking a cruise in the Arctic but the fact that the climate is changing influenced them to do it now.”

To Dawson, this exposes a dark irony. Tourists may further endanger the Arctic's environment, but their experience may also result in them taking action to protect it after returning home.

“These trips really do change people," she said. "The Arctic is full of magic. It is one of the most beautiful places on earth."